Process of making commutator blocks for cathode ray tubes



ug. 31, 1937.l

J. KEssLr-:R- y v2,091,863- PRocEss loF MAKING comauruon noxs Fon cATHoDE RAY TUBES Filed April a.. 1955 ATTOR N EY Patented Aug. l31, 19.37y

aosLsss PROCESS F MAKING COMMUTATOB BLOCKS FOR CATHODE BAY TUBES Jacob Kessler, Richmond Hill,v N. Y. Application April 8, 1935. Serial No. 15,324 3 Claims. (Cl. 25o-27.5)

This invention relates to a process employedV in the construction offcathode rayl tubes, particularly of the type lshown herein and shown, described -and claimed in my co-pending application Serial. No. 15,325, illed April 8, 1935, and entitled Cathode ray tubes.

An object of the present invention is the provision of o. method for constructingl an important element of the cathode ray tube of my invention, said element being termed by mea commutator' block. I

The invention comprises a method whereby photo-sensitive material adapted to'supply electrons when effected by light, may be deposited on the ends of the individual conductors comprising the mentioned block; if said light-sensitive material is easily oxidized the process is performed in a non-oxidizing atmosphere.

In the drawing:

Fig. 1 is a sectional view of apparatus employed in carrying out the process of my invention, the view showing the block within the apparatus.

Fig. 2 is a view of a cathode ray transmitter tube, partly in section, partly in elevation, and

partly broken'away. 4

Fig. 3 is a fragmentary elevational viewv of the light end of. the commutator block which forms part of the tube shown in Fig. 2: and

Fig. 4 is a fragmentary longitudinal section -of the same block.

Referring to the drawing, and at rst to Figs. 2, 3 vand' 4, the numeral 5 indicates an incaride scible filament adapted to serve as the cathode ray source. YProngs 6 Which'project from base 'l vlof the cathode ray tube are the terminals of the lament, while a prong 8, which also projects lfrom the base l, is the terminal of a well-known -Wehnelt controlicylinder 9 which encircles the iilament 5. A sealed bulb 'or envelope I'll is held -in the base l and contains the parts illustrated as being thereimjsaid bulb being evacuated of air and filled with an ionizable gas, said gas being,

for example, argon at a few millimeters o! merr cury pressure. An electrode I2 is positioned within the tube infrontof `the filament and has a central aperture l2a thru'which the cathode rays may pass. The electrode l2 has a terminal l2b 'outside of the bulb lo. as shown, and 1s to be charged with a positive potential at, for example, three or four thousand volts, in order. vto give a high velocity to thev cathode rays. Two pairs otdeector plates, designated respectively by the numerals II and I0, and positioned at right angles to each other, are also contained withinthel bulb lll and are in front ofthe disc l2'. Each of' the electrodes l5 and I8 is provided with terminals numbered respectively IIa and ISa, which terminals are exterior to the -envelope or. bulb.

' The deector plates l5 and I3 and their operation ln the cathode ray tube are well known. and are for the purpose of de'flecting .the cathode rays sol that they may be directed to'predetermined positions when charged respectively to varying potentials, the varying potentials of each pair being out of phase With the other pair, as well known. i i

In front of the deector plates, and in the forward portion of the bulb l0, what I call a commutator block is positioned, and itis designated by the numeral l1, being held in spaced relation v to the wall of the bulb by means of insulators I B. The block l1 has a plane front face I9 and a dlshed face Ia upon which latter face the cathode rays fall. lThe face I9a is a sphericalsurface so formed that all `rthel rays may be normal to that part of the face on which they fall. vThe block I1 includes a plurality of straight electrical conductors Ila insulated from each other. The` 4conductors lla may be of any suitable material,

such for example as copper wire, which has been coated with aluminum, the latter being subsequentl'y converted into the oxide to function as insulating means, such insulation being designated by the character l'lb. It is to be understood however that the ends oi.' the conductors or wires lla. are not insulated. The forward ends of the conductors lla, i. e., those which lie in the forward face i9, are preferably pitted to receive small masses llc of light-sensitive material, such as sodium, for 4example, or other material adapted'to emit electrons when acted'on by light or other suitable electromagnetic waves. It is to be understood that the mentioned light-sensitive or photo-electric material lodged in the ends of the conductors comprising the block Il are separated from each other by the insulating medium ilb which surrounds each conductor or wire.

Within the envelope lll and three or four inches, for example, in front of the block I1 is a collector plate having a terminal 2l outside of the envelopejso that it` may be charged toapositive potential of volts, for example; from any suitable source. The mentioned plate 2li is to'be charged'to a potential suillcient to enable it to collect the'electrons emanating from the photosensitive material llc. The collector plate 20 is 20a thru which an Il ofthe block provided with an aperture image 'may be thrown on the face il, using an appropriate optical system 23 which is positioned in front of the envelope I and exterior thereto for the purpose of forming the image on the mentioned face. The collector plate 20 being positively charged, a negative charge will be induced in the /forward ends of the conductors Ila and in the photoelectric material Hc with a resultant positive charge on the rear ends of the conductors ila, which positive charge in the mentioned rear ends of the conductors Ila will be neutralized by the cathode rays, the electrons from the photo-electric material I lo then being free to be pulled by the collector plate to the latter. It l5 will be understood that the cathode ray beam falls on the conductors Ila successively, that is, on one conductor at a time, moving then to an adjacent conductor as controlled ,by the charged deector plates, the electrons from the corre- 2@ spending photo-electric masses being thereby successively released for collection on the accumulator or collector plate with a resulting varying potential thereon. The mentioned resulting varying potential is due to the varying electron emission from the photo-sensitive material in accordance with. the varying intensity of light falling on the diderent light-sensitive masses lodged in the several conductors, it being readily understood that when an image is thrown on the Surface IS of the block Il the various masses of photo-sensitive material will be variously illuminated.

The present invention ls concerned with the preparation of the block Il. Said block maybe made from conducting wires which have' been coated with a metal, the oxide of which is an insulator. Such a metal coating may be of aluminum which may be converted into the oxide by any suitable method, as for example, the electrolytic method or by means of heat. The wires comprising the block will thereby be insulated from each other.

The wires which comprise -the commutator block Il, and which are from 3 to 5 mills in diameter, may be of a copper-aluminum alloy having a composition of 70 per cent copper and thirty per cent aluminum. In order to provide an insulating coating for such alloy wire, I remove from the alloy the copper which exists at and adjacent the surface or periphery; this may be accomplished electrolytically byl making the l wire the anode in an electrolytic system provided with a cathode and with an electrolyte of coppersulphate solution or other suitable dissolved copper salt. The outer surfaces of the wires after the procedure just mentioned, consist ofV aluminum which is to be changed to aluminum oxide; this conversion may be effected by heat or electrolytically. If the conversion is to be effected electrolytically the wires are made the anode in a system comprising a. cathode and an electrolyte of sodium silicate, ammonium borate or other suitable salt, the voltage on the system being sufllcient to oxidize the aluminum coating of the wires. f

'I'he image ends of the wires comprising Vthe block, that is, the ends forming the face I9 of the block, after assembly to form the latter, are

pitted or roughened by any suitable process in order that photo-sensitive material may be deposited on the mentioned ends of the wires and adhere thereto. The pitting or roughening may be effected by electrolysis, the latter process being employed to remove copper from the men- 75 tioned ends of the wires, which, as above'stated,

accises may be made of a copper-aluminum alloy, it being understood that the block is made the anode in an electrolytic system similar to that used for the removal oi copper from the wires at and adjacent their peripheries. The wires of the block may be made of an alloy, one constituent Yof which is a metal whose oxide is an insulator.

The commutator blockLwhich is provided with a band Ild extending beyond the face i9 thereof, is then placed in a casing 35 and the casing with the block therein is positioned on a 'support 36 within a container 3l, as shown in Fig. l. It will be noted that the image face I9 of the block il is uppermost in the casing 35, the rim of the latter extending about one-eighth of an inch above the .upper face of the block. A tube 36 in which sodium may be vaporized and thru which sodium vapor may pass and be deposited on the upper face of the block il, is sealed into one end of the container 3l intermediate its ends and extends from the outside to thekinside oi said container, the inner end of said tube belng turned downwardly and positioned above the block Il. A tube tl'thru which petroleum burning oil maybe passed and be delivered onto the block il after the sodium has been deposited thereon is also sealed into thecontainer 3l, be-

ing positioned vertically and over the block Il. A further tube SI is also sealed into one end of the container tl and is provided to admit hydrogen into the container.

After the block il, together with the casing 35 in which it is contained, has been placed in the container 3l, the air is evacuated from the container 3l thru an exhaust'passageway 42. The

mentioned container is then ushed only or more the container 31 thru the tube 40 to cover the deposit of sodium existing on the block I1. The

y mentioned block, together with the casing 35 in which it is contained, is then removed, coated and covered face up, from the container 31 and is immersed, in similar position, in a. bath of petroleum burning oil which may be heated'to 92 C. to soften the sodium. While the block is in the mentioned bath of petroleum burning oil, i

the excess sodium is scraped oil', preferablywith ne steel wool less than l mill inv diameter so that no sodium remains on the insulation existing around the individual wires comprising the block. 'I'he block is then taken out of the oil bath and put into a bath of petroleum ether, to 80 C., B. P., to be thoroughly washed. The block is then taken out oi' the bath of petroleum ether with some of the latter covering the sodium and is placed image face up in the cathode ray tube shownA in Fig. 2, this tube however being positioned vertically with its base lowermost. It will thus be seen that the deposit of sodium on the block is'never exposed to the atmosphere and thus is not in danger or being oxidized. All possible care should be taken not to oxidize the Een.

The bulb or envelope I0 of. the cathode ray tube is then exhausted of air thru a suitable -opening 46 and is then flushed with hydrogen opening.` The current of hydrogen evaporates the petroleum ether from the image face of the block. Hydrogen at a few millimeters of mercury pressure may then be admitted to the tube. l

A glow discharge kis then passed thru the tube f using the filament 5 and the collector plate 2li terial adapted to emit electrons when acted on' as terminals of the discharge. The hydrogen is then'blown out and the tube flledwith argon at a few millimeters of mercury pressure, the argon being sealed therein and functioning as a permanent ionizahle medium which,l is to be acted on by the cathode beam and by the photolelectrons from the image surface of the block, it being understood that the passageway 45 is sealed as the tube is filled with argon.

What is claimed as new is: 1. The method of preparing a commutator block for a cathode ray tube, which block includes a bundle of insulated conducting wires, said method comprising depositingon corresponding ends of said wires a light-sensitive matective coating, placing the block, with said protective coating thereon, in a cathode lray tube. and removing said coating in a non-oxidizing environment.

2. The methody oi.' preparinga commutator block for a cathode ray tube, which block includes a. bundle of insulated conducting wires, said method Y comprising depositing on corresponding ends of said wires'a light-sensitive material adapted to emit electrons when acted on by light, the deposition of said material being performed in a non-oxidizing environment, covering said light-sensitive material with a protective coating,

vplacing the block, with said protective coating '-thereon, in acathodeA ray tube, removing said coating in a non-oxidizing environment, and sending an electric dischargel thru said tube.

3; The method of preparing aA commutator block for a'cathocle ray tube, which bloei: in

cludes a1 bundle of insulated conducting wires,

said method comprising depositing on' corre` spending ends of said wires a light-sensitive material adapted to emit electrons when acted on by light, the deposition of saidmaterial 'being performed in a A'non-oxidizing environment, covering said light-sensitivev material with aprotective coating, placing the block, with said pro- *tective coating thereon, in a cathode ray tube,

`removingsaid coating in a non-oxidizing en- 

